1. Field of the Invention
The present invention relates to a punching tool, and more particularly to a punching tool used for a punching press or a turret punch press.
2. Description of the Related Art
In FIG. 1, a conventionally popular punching tool 101, for example, used for a turret punch press is shown. There are a hole punching tool, a forming tool and the like as the punching tool 101, however, in this case, the punching tool 101 as the forming tool is exemplified.
A punch driver 103 is provided above a punch P, and a male screw 105 is provided on an outer periphery of an upper end portion of the punch driver 103. A punch head 109 having a female screw 107 meshing with the male screw 105 formed inside is provided in the upper end portion of the punch driver 103, and a fastening ring 111 meshing with the male screw 105 of the punch driver 103 in the same manner is provided in the lower side of the punch head 109.
Accordingly, the punch head 109 and the fastening ring 111 can be fixed to the punch driver 103 by fastening them by means of a plurality of bolts 113 due to a mutual operation.
A punch guide 115 having a space therewithin is integrally mounted to the lower side of the punch driver 103, and a punch body 117 is provided in the inner space in a freely movable in a vertical direction. A urethane rubber 119 as an elastic body is inserted to the lower side of the punch body 117 in the inner space, and a punch tip 121 is provided in the lower side of the urethane rubber 119 in a freely movable in a vertical direction.
On the contrary, a die D is provided in a lower side in such a manner as to be opposite to the punch P. In the die D, a die tip 125 is fixed to a die body 123 by a bolt 127 and a mounting pin 129 so as not to rotate, and an ejector 131 is provided in a periphery of the die tip 125 so as to be urged upwardly by a spring 133.
In accordance with the structure mentioned above, the bolt 113 is loosened so that the punch head 109 and the fastening ring 111 are made in a rotatable state with respect to the punch driver 103, the punch head 109 is vertically moved by a rotation thereof, and the punch P is set to be a punch height corresponding to a thickness of a workpiece W and a processing condition. When the punch height is set to be a desired height, the bolt 113 is fastened so as to fix the punch head 109 and the fastening ring 111. Thereafter, the workpiece W is positioned between the punch P and the die D, and the punch head 109 is struck by a striker of the turret punch press so as to perform a desired punching process.
However, in the prior art of this kind, in the case of setting the punch P to be a desired punch height, since it is necessary to accurately measure a punch height by a Vernier calipers or the like after loosening the bolt 113, rotating the punch head 109 and adjusting the punch height, there are problems that the operation is very troublesome and requires a skill.